As the saying goes, there are three poisons in a medicine, and men who take Viagra must also have certain side effects, and the more you eat the greater the side effects. First, some patients will have a headache, the more Viagra eaten, the more intense the headache will be. Secondly, some patients will experience dizziness and blurred vision. Third, long-term use of Viagra can lead to abnormal erections in men, and may even have symptoms of premature ejaculation. Fourth, blood pressure may be lowered and may even cause life-threatening effects. Fifth, temporary deafness may occur, and some patients may experience infertility, or affect male sleep, or even lead to reduced male fertility. More serious ones may also endanger the life of the patient, so it is not recommended that men take Viagra for a long time, thus avoiding dependence.